This site uses the EPUB format to view books. This was chosen because it is fast and safe - the books load in parts and you can't rip books from the site and share them somewhere else. Many authors write their books in Word or Scrivener and end up with a Word or PDF file as the end result. To upload your book to the site, you'll need to have it in EPUB format. If you want to know more about EPUB, check out this wikipedia page. You can use online tools or download programs to convert your existing Word or PDF file to EPUB, or you can hire someone to do it for you (like I did on Fiverr.com). The point is, an EPUB file is like a website where different files work together to present a full page. Just as a website combines html, css, js files as well as images, so does an EPUB file combine files to present an ebook. This means that converting from PDF or Word is not as straightforward as we'd like (it's also not simple to convert a Word doc or a PDF file to a proper webpage). But, just as with webpages, EPUB files are an open standard and are the current future-proof, most flexible way to view books. So, make the effort to get your book converted to EPUB and upload it to the site to start raking in reviews.